Re: [GHC] #14119: Refactor type patterns

#14119: Refactor type patterns -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: 12564, 13910, | 13938, 14038 Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"9218ea60faa744803fb41066aedd1da8f1bd9185/ghc" 9218ea60/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="9218ea60faa744803fb41066aedd1da8f1bd9185" Interim fix for a nasty type-matching bug The type matcher in types/Unify.hs was producing a substitution that had variables from the template in its range. Yikes! This patch, documented in Note [Matching in the presence of casts], is an interm fix. Richard and I don't like it much, and are pondering a better solution (Trac #14119). All this came up in investigating Trac #13910. Alas this patch doesn't fix #13910, which still has ASSERT failures, so I have not yet added a test. But the patch does fix a definite bug. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14119#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler